This invention relates to briquetting machines and methods such as are used to form shapes from particulate materials. In particular it relates to means for forming briquettes from partially reduced iron ore. The invention in one embodiment represents an improvement on the device shown in U.S. Pat. No. 3,077,634 to Komarek et al., the specification of which is adopted as part of this disclosure.
Komarek shows a briquetting machine characterized by a cylindrical central body having U-shaped recesses for accommodating mold inserts. These cylindrical units are placed in tandem so that faces of two molds oppose each other as the cylinders turn, compressing the particulate material which falls between them. Temperatures of the gas inside the briquetting machine are about 1,100.degree. - 1,400.degree.F. Because of the large quantity of dust which is generated inside the hopper leading to the compressing zone, it has been necessary to seal off the entire machine from the atmosphere in order to prevent explosions. The large opaque housing, however, has rendered it difficult to cool the machine with water sprays and impossible to see the mold inserts for inspection; moreover, it has not been entirely free from the hazards of combustion.
Accordingly, the principal object of this invention is to provide a means of permitting the briquetting roll to rotate from the inside sealed portion of the machine to an exposed outside unsealed portion of the machine, with a seal or barrier between the inside and outside portions of the machine that does not physically contact the rotating roll. The reasons for not having a physical contact are (1) uneven surfaces on the roll of up to 0.010 inch, (2) differences in roll dimensions of up to 0.060 inch due to expansion caused by operating temperature changes, and (3) movement within the briquette machine of the briquetting roll of up to 1 inch due to operating adjustments. Benefits of the invention include longer roll life, a reduction of "stickers" in the roll pockets, and operator ability to see problems develop on the roll face before they become serious.